Name some actors that made you wonder why

It's interesting to note that you started this thread exactly ten days before Rex Reason died at age 86 on November 19, 2015.

It's really not too surprising he didn't go further. He was a competent actor and good-looking man but didn't have the range or depth to carry him too far, or that spark of personality that sometimes makes up for talent. Reason was just a solid, dependable second-lead type, a fair actor of limited range without that indefinable something that makes a star. He quit acting in the early 60s and went into real estate, where he became quite successful. He seems to have been a decent guy who had a modest run in movies and TV for a time, which is more than most people can claim.

Jeff Morrow was clearly the best performer in this film. No slight against Rex Reason, but Morrow had the best role and turned in the best performance of his career. Morrow was another nice guy who managed a modest career that lasted several decades (he had come from Broadway and radio and didn't make his first film until The Robe in 1953, when he was 46) and he continued to act into the 1980s. In general he wasn't that good an actor but he was serviceable enough to stay in the business for over 40 years, which isn't bad at all, though I'm sure he had some business on the outside to help pay the bills. But he showed he could give a nuanced and understated performance in This Island Earth.